Supervisory device for a sheet feeder

ABSTRACT

A supervisory device for protecting a sheet feeder against damage or operational failure as may be caused by sheets with turned-over edges or the presence of foreign material such as wastepaper pieces, etc. on sheets conveyed by the sheet feeder, has swingably mounted probe rollers which let the sheet flow past without being acted upon by the same but one or more which are lifted out of a normal or rest position by engagement with a sheet with a turned-over edge or with foreign material. Lifting of any one of the probe rollers initiates suitable control functions such as stopping the sheet feeder. The device also includes means neutralizing the effect of temporary shocks or vibrations experienced by the probe rollers of the device upon engagement of the leading edges or the trailing edges of sheets with the rollers.

United States Patent [72] Inventor Adolf Schwebel, Offenbach am Main,

Germany [21] App]. No. 865,567

[22] Filed Oct. 13, 1969 [45] Patented Oct. 19, 1971 [73] Assignee Mabeg Maschinenbau GmbH Nachl. Hense 8: Pleines GmbH. & Co. Offenbach am Main, Germany [32] Priority Dec. 7, 1968 [33] Germany 54] SUPERVISORY DEVICE FOR A SHEET FEEDER 1 1 Claims, 4 Drawing Figs. I US. Cl

3,123,355 3/1964 Lessig 3,354,273 11/1967 Bleiman ABSTRACT: A supervisory device for protecting a sheet feeder against damage or operational failure as may be caused by sheets with tumed-over edges or the presence of foreign material such as wastepaper pieces, etc. on sheets conveyed by the sheet feeder, has swingably mounted probe rollers which let the sheet flow past without being acted upon by the [52] 271/56 same but one or more which are lifted out ofa normal or rest [51] II?!- C] B6511 osition by engagement with a sheet with a turned-over edge [50] Field of Search 271/57, 56, or i h f i e iaL Lifting of any one of the probe rollers /1 128 initiates suitable control functions such as stopping the sheet feeder. The device also includes means neutralizing the effect 56 1 References Cited of temporary shocks or vibrations experienced by the probe UNITED STATES PATENTS rollers of the device upon engagement of the leading edges or 1,850,108 3/1932 Hunter et a1 271/57 UX the trailing edges ofsheets with the rollers.

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comers.

BACKGROUND There are known supervisory devices of the general kind above referred to which include roller systems to carry out the required supervisory functions.

Supervisory devices as heretofore known, are not sufficiently sensitive and do not function in a sufficiently reliable manner. They also tend to respond to shocks such as caused by vibrations experienced by the roller system. Shocks are likely to occur when the leading and the trailing edges of sheets engage and leave respectively the rollers while passing beneath the same. Activation of the supervisory devices in response to such shocks is, of course, not necessary and in fact, highly undesirable.

Another disadvantage of the now known supervisory devices is that they are not capable of responding to the presence of foreign material such as pieces of wastepaper which are present in the spaces between the edges of sheets conveyed in shingled or overlapped fashion as is now very customary.

THE INVENTION It is an object of the invention to provide a novel and improved supervisory device of the general kind above referred to which is highly reliable in operation but not sensitive to the aforereferred to operationally occurring shocks; in other words, the device of the invention does not initiate the operation of the feeder in response to shocks.

It is also an object of the invention to provide a novel and improved supervisory device of the general kind above referred to which responds to the presence of any foreign material or sheets with folded-over edges within the range of the supervisory device irrespective of the location of such foreign material or faulty sheets.

The aforepointed out objects, features and advantages and other objects, features and advantages which will be pointed out hereinafter are obtained by providing transverse of the travel direction of the aligned probe members, preferably rollers, which remain in a rest position when sheets free of foreign material and good sheets pass the rollers but are individually or together lifted into an operational position by the presence of foreign material or faulty sheets. Lifting of one or more rollers into the operational position changes the differential pressure between opposite sides of a diaphragm. The resulting change in the deflection of the diaphragm is utilized to activate a control circuit for the sheet feeder or the machine itself. Activation of the control circuit may effect, for

instance, stoppage of the sheet feeder or of the machine associated therewith.

DETAILED DESCRIPTION OF THE SUPERVISOR! DEVICE In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational view of a supervisory or control device according to the invention;

FIG. 2 is a plan view ofFIG. 1;

FIG. 3 is a side view, partly in section, ofFIG. 1; and

FIG. 4 is a fragmentary plan view of FIG. 3 turned through 90.

Referring now to the figures more in detail, the exemplified supervisory device comprises a shaft 3 mounted in sidewalls l and 2 of the frame structure of the machine such as a printing press which is not further shown as it does not constitute part of the invention. Shaft 3 supports three carriers 4, 5 and 6 for rollers, 7, 8 and 9 respectively. These rollers constitute probe rollers disposed in alignment and independently swingable about the axis of shaft 3. Each roller is preferably mounted in diagrammatically indicated ball or roller bearings by trunnions 10 to inclusive. The trunnions of the rollers are separate from each other so that the probe rollers are free to swing independently. As is shown, each probe roller assembly is supported on shaft 3 by a frame structure. The frame structure for probe roller 7 has arms 25 and 22, the'frame structure for probe roller 8 has arms 16 and 17 and the frame structure for roller 9 has arms 23 and 60.

Arms 16 and 17 of roller 8 also mount valve members 18 and 19 respectively. The valve members preferably include nozzles the distance of which relative'to roller 8 is selectively settable. The valve nozzles are closable by closure members 20 and 21 mounted on support arms 22 and 23 respectively. The closure members close the nozzles when the probe rollers are in the position shown in FIGS. 1 and 2. This position constitutes the rest or inactive position of the rollers. The support arm 25 for the outer end of roller 7 mounts a closure member 24 for the valve member of a relief or poppet valve 26. This valve member is mounted by means of an arm 27 pivotal on shaft 3 but it may also be pivotally mounted on a separate pivot. The relief valve constitutes a control means as will be hereinafter described.

It should be pointed out in this connection, that while three probe rollers are shown, the concept of the invention is not limited to three rollers; a smaller or larger number may also be used or there may be a single probe member. Moreover, as pointed out before, the probemembers need not be in the form of rollers although such arrangement is preferred.

The supervisory device further comprises a control means in the form of a closed housing 32 which is divided by a diaphragm 34 into two compartments 31 and 33. Compartment 3] is connected by a conduit 28 to 'a-supply 40 of pressure fluid such as pressurized air. The pressure supplyis diagrammatically indicated by a compressor. The compartment is further connected by a branch conduit 28a to the relief valve. Compartment 33 is connected by a second conduit to compressor 40. This conduit is further connected by a branch conduit 29 to valve 18, 20 and by a branch conduit 30a to valve 19, 21.

Pressure control valves 41 and 42 are included in conduits 28 and 30. The valves are so set that the pressure P in compartment 31 is higher than the pressure I in compartment 33 by a selected value.

Diaphragm 34 mounts a switch actuating member 35 which coacts with switch contacts 36 and 37 included in a control circuit 38, 39 for controlling the operation of the sheet feeder and/or the sheet processing machine. The necessary circuitry is diagrammatically indicated by a box 61 and should be visualized as being conventional. The pressure differential P:Pl is so selected that in normal operation, diaphragm 34 is deflected into a position in which switch actuating member 35 is in the full line position, that is, contacts 36 and 37 are open.

Sidewall 1 mounts a staybolt 44 through which a setscrew 46 is threaded and similarly sidewall 2 mounts a staybolt 45 through which a setscrew 47 is threaded. Setscrews 46 and 47 coact with arms 25 and respectively to permit to set the three probe rollers 7, 8 and 9 for any desired minimal distance from a conveyor roller 48 of the sheet feeder just permitting free passage of clean sheets, said position constituting the rest position of the rollers.

FIG. 3 shows the staybolt and setscrew arrangement for arm 60 in detail and also a stack of sheets from which successive sheets 49, 51 and 52 are withdrawn in a conventional manner and conveyed in shingled or overlapped arrangement on a table 66. The figure further shows a piece of wastepaper 53 and FIG. 2 shows sheet 49 as having a folded-over edge 50.

The operation of the supervisory device as hereinbefore described is as follows:

Prior to starting the sheet feeder the supervisory device is set by means of setscrews 46 and 47 so that a conveyor roller 48 does not engage any of the probe rollers and hence, does not drive the same. As previously described, the pressure differential between compartments 31 and 33 is so set that the higher pressure P in compartment 31 holds switch actuating member 35 in the full line position.

When the sheet feeder is now started, the edges of sheets engaging or leaving the probe rollers as they are being conveyed tend to shake the probe rollers thereby causing slight temporary lifting of the same. The shocks thus experienced by the probe rollers are or may be sufficient to separate the valve member 26 of the relief valve abruptly from its closure member 24 since the inertia of arm 27 mounting the valve member is much smaller than the inertia of the mass of the probe rollers. Such temporary and repeated opening of the relief valve permits escape of pressure air in compartment 31 via conduit 280. As a result, the pressure in compartment 31 decreases and thus balances temporarily the pressure in compartment 33 or even becomes somewhat lower than in this compartment. The resulting change in the deflection of diaphragm 34 moves the switch actuating member 35 somewhat to the left, that is, into a position further removed from switch contacts 36, 37 than shown in full lines. As is now evident, the provision of the relief valve and the coaction thereof with the diaphragm system nullifies the effect of shocks experienced by the probe rollers as previously described thereby avoiding unnecessary and undesirable control functions.

Let it now be assumed that the folded-over edge 50 of sheet 49 or the piece 53 of wastepaper presumed to be in the space between sheets 49/51 and 51/52 becomes engaged with roller 9. As a result, the roller is lifted out of its rest position into an operational position. Due to and during such lifting of roller 9 both valve member 19 and valve closure member 2] are simultaneously lifted so that this valve remains closed but the valve between 'probe rollers 7 and 8 is opened as valve member 18 is also lifted via roller 8 but closure member on roller 7 is not lifted as this roller remains in its rest position. Hence, chamber 33 is now vented via conduits and 29. As a result pressure differential PzPl increases and the diaphragm is now deflected into a position in which switch actuating member closes contacts 36, 37 as is indicated by dotted lines thereby initiating the required control functions via the circuitry in control box 61. Such control functions may stop the sheet feeder and/or the sheet processing machine such as a printing press.

Assuming now that probe roller 8 is lifted by engagement with wastepaper or a faulty sheet, both valve members 18 and 19 are then separated from their closure members 20 and 21, respectively. As a result, compartment 33 is vented via conduits 29 and 30a thereby causing closing of switch contacts 36 and 37 as previously described.

Engagement of probe roller 7 with wastepaper or a faulty sheet causes simultaneous lifting of valve members 26 and 18 and their closure members 24 and 20 respectively so that these two valves remain closed but valve member 19 is also lifted while its closure member 21 remains stationary. Hence, compartment 33 is vented via conduit 30a thereby causing closing of switch contact 36 and 37 as previously described.

Sheets free of foreign material and without deformation for instance due to folded-over edges will pass the probe rollers without acting upon the same.

What is claimed is:

1. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination:

a conveyor for conveying a flow of successive sheets along a predetermined path;

elongate probe means for detecting the presence of foreign material or of a partly folded-over sheet;

a support means for supporting said probe means transverse of the conveyor path and parallel thereto in a rest position in which the distance of the probe means from the conveyor path is such that the flow of sheets just can pass the probe means but present foreign material or a partly folded-over sheet presses against the probe means, said support means including movable means normally holding the probe means in said rest position but in response to pressure as caused by presence of foreign material or of a partly folded-over sheet against said probe means moving the same into an operational position; and

control means controlled by the movement of the probe means into said operational position and controlling a supervisory circuit,

said control means including a diaphragm, a first pressure fluid conduit for feeding pressure fluid to one side of said diaphragm, a second pressure fluid conduit for feeding pressure fluid at a lower pressure to the other side of the diaphragm, and a switch means included in said supervisory circuit and coupled to said diaphragm for control by the deflection thereof, and

said conduits being arranged to be closed and opened in response to the probe means being held in said rest position and in said operational position respectively.

2. The device according to claim 1 wherein said control means further comprise a closed housing, said diaphragm dividing said housing into two compartments, the first one of said conduits being connected to one of said compartments and the second conduit being connected to the other of said compartments.

3. The device according to claim 1 wherein said movable means comprise two valves each held in the closed position when said probe means is in its rest position and in the open position in response to a movement of said probe means into its operational position each of said valves including a valve member and a valve closing member, each of said valve closing members being supported by the probe means and closing the respective valve member in the rest position of the probe means, movement of the probe means into the operational position separating at least one closing member from the respective valve member thereby causing a corresponding change in the diflerential pressure between the sides of the diaphragm.

4. The device according to claim 3 wherein the distance between the valve members and the probe means is adjustable.

5. The device according to claim 1 wherein a pressure control valve is included in each of said conduits for independently varying the pressure fed therethrough to the opposite sides of the diaphragm.

6. The device according to claim 1 wherein said conveyor comprises an elongate roller disposed parallel to the lengthwise axis of said probe means, and adjustment means coacting with said probe means for gradually and selectively varying the spacing between the probe means and the roller.

7. The device according to claim 1 wherein said device constitutes a self-contained structural unit which is attachable as a unit to a sheet processing machine.

8. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination:

conveyor means for conveying a flow of sheets along a predetermined path:

a plurality of aligned probe rollers;

support means supporting said rollers transverse of said path parallel thereto and independently swingable between a rest position of the rollers in which a flow of sheets free of foreign material or of a partly folded-over sheet just passes the rollers without exerting pressure thereupon and an operational lifted position of the rollers due to pressure applied thereto by foreign material or a partly folded-over sheet;

control means coacting with said probe rollers to be operated by lifting of any one of said rollers into the operational position, operation of said control means controlling a supervisory circuit for the sheet feeder; and

shock absorbing means activated in response to operational shocks experienced by said probe rollers, said shock absorbing means maintaining said control means inactive during the occurrence of such shocks.

9. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination:

a conveyor for conveying a flow of successive sheets along a predetermined path;

a probe means for detecting the presence of foreign material or of a partly folded-over sheet, said probe means including a plurality of aligned rollers;

roller support means including a shaft common to the probe rollers and extending transverse of and parallel to said conveyor path, a support frame for each of the rollers, each of said support frames supporting the respective roller independently swingable about the shaft toward and away from said conveyor path, and setting means for each frame limiting the distance of each roller from the path to a distance at which a flow of sheets free of foreign material or of a partly folded-over sheet just can pass the rollers but pressure engagement with foreign material or of a partly folded-over sheet with one or more of the rollers causes lifting of the respective roller or rollers above said distance;

first control means controlling the operation of the sheet feeder, said first control means including a diaphragm, first conduit means supplying pressure fluid to one side of the diaphragm, second conduit means supplying pressure fluid of a lower pressure to the other side of the diaphragm, and a sheet feeder control circuit means including a switch means, said switch means being operated by a switch actuating member controlled by the deflection of said diaphragm, said switch actuating member being held in one switching position in response to a predetermined pressure differential across the diaphragm and being moved into another switching position in response to an increase of said pressure differential, said change in the switching position of said member controlling the sheet feeder; and

second control means controlling the first control means, said second control means including a valve means interposed between each end of an intermediate roller and the adjacent end of the respective outer roller, each of said valve means being connected to the second conduit means and having a valve body mounted on said intermediate roller and a valve closing member mounted on the adjacent end of the respective outer roller whereby lifting of any one of said probe rollers due to the presence of foreign material or of a partly folded-over sheet opens one of said valves causing escape of pressure fluid from the second conduit means, said escape increasing the pressure differential across the diaphragm thereby changing the switching position of the switch means, and

said second control means further including a relief valve means connected to the first conduit means and having a movably mounted valve body and a valve closing member supported on the other end of one of the outer probe rollers whereby shocks experienced by the probe means causes the closing member of the relief valve to move into a position opening the relief valve means, said opening of the relief valve means permitting escape of pressure fluid from the high-pressure side of the diaphragm, said escape of pressure fluid causing a decrease of the pressure differential thereby maintaining the switch means inactive.

10. The device according to claim 9 wherein said first control meansfurther comprise a closed housing, said diaghragm dividing said housing into two compartments, one of t e conduits being connected to one compartment and the other conduit to the other compartment, said switch actuating member being supported by the diaphragm for movement in unison with the deflections thereof.

1 1. The device according to claim 9 wherein the valve body of said relief valve means is swingably supported on said shaft. 

1. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination: a conveyor for conveying a flow of successive sheets along a predetermined path; elongate probe means for detecting the presence of foreign material or of a partly folded-over sheet; a support means for supporting said probe means transverse of the conveyor path and parallel thereto in a rest position in which the distance of the probe means from the conveyor path is such that the flow of sheets just can pass the probe means but present foreign material or a partly folded-over sheet presses against the probe means, said support means including movable means normally holding the probe means in said rest position but in response to pressure as caused by presence of foreign material or of a partly folded-over sheet against said probe means moving the same into an operational position; and control means controlled by the movement of the probe means into said operational position and controlling a supervisory circuit, said control means including a diaphragm, a first pressure fluid conduit for feeding pressure fluid to one side of said diaphragm, a second pressure fluid conduit for feeding pressure fluid at a lower pressure to the other side of the diaphragm, and a switch means included in said supervisory circuit and coupled to said diaphragm for control by the deflection thereof, and said conduits being arranged to be closed and opened in response to the probe means being held in said rest position and in said operational position respectively.
 2. The device according to claim 1 wherein said control means further comprise a closed housing, said diaphragm dividing said housing into two compartments, the first one of said conduits being connected to one of said compartments and the second conduit being connected to the other of said compartments.
 3. The device according to claim 1 wherein said movable means comprise two valves each held in the closed position when said probe means is in its rest position and in the open position in response to a movement of said probe means into its operational position each of said valves including a valve member and a valve closing member, each of said valve closing members being supported by the probe means and closing the respective valve member in the rest position of the probe means, movement of the probe means into the operational position separating at least one closing member from the respective valve member thereby causing a corresponding change in the differential pressure between the sides of the diaphragm.
 4. The device according to claim 3 wherein the distance between the valve members and the probe means is adjustable.
 5. The device according to claim 1 wherein a pressure control valve is included in each of said conduits for independently varying the pressure fed thereThrough to the opposite sides of the diaphragm.
 6. The device according to claim 1 wherein said conveyor comprises an elongate roller disposed parallel to the lengthwise axis of said probe means, and adjustment means coacting with said probe means for gradually and selectively varying the spacing between the probe means and the roller.
 7. The device according to claim 1 wherein said device constitutes a self-contained structural unit which is attachable as a unit to a sheet processing machine.
 8. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination: conveyor means for conveying a flow of sheets along a predetermined path: a plurality of aligned probe rollers; support means supporting said rollers transverse of said path parallel thereto and independently swingable between a rest position of the rollers in which a flow of sheets free of foreign material or of a partly folded-over sheet just passes the rollers without exerting pressure thereupon and an operational lifted position of the rollers due to pressure applied thereto by foreign material or a partly folded-over sheet; control means coacting with said probe rollers to be operated by lifting of any one of said rollers into the operational position, operation of said control means controlling a supervisory circuit for the sheet feeder; and shock absorbing means activated in response to operational shocks experienced by said probe rollers, said shock absorbing means maintaining said control means inactive during the occurrence of such shocks.
 9. A supervisory device for safeguarding the operation of a sheet feeder for feeding a flow of successive sheets to a sheet processing machine against failure and damage as may be caused by the presence of foreign material such as pieces of wastepaper etc. or of a partly folded-over sheet, said device comprising in combination: a conveyor for conveying a flow of successive sheets along a predetermined path; a probe means for detecting the presence of foreign material or of a partly folded-over sheet, said probe means including a plurality of aligned rollers; roller support means including a shaft common to the probe rollers and extending transverse of and parallel to said conveyor path, a support frame for each of the rollers, each of said support frames supporting the respective roller independently swingable about the shaft toward and away from said conveyor path, and setting means for each frame limiting the distance of each roller from the path to a distance at which a flow of sheets free of foreign material or of a partly folded-over sheet just can pass the rollers but pressure engagement with foreign material or of a partly folded-over sheet with one or more of the rollers causes lifting of the respective roller or rollers above said distance; first control means controlling the operation of the sheet feeder, said first control means including a diaphragm, first conduit means supplying pressure fluid to one side of the diaphragm, second conduit means supplying pressure fluid of a lower pressure to the other side of the diaphragm, and a sheet feeder control circuit means including a switch means, said switch means being operated by a switch actuating member controlled by the deflection of said diaphragm, said switch actuating member being held in one switching position in response to a predetermined pressure differential across the diaphragm and being moved into another switching position in response to an increase of said pressure differential, said change in the switching position of said member controlling the sheet feeder; and second control means controlling the first control means, said second control means including a valve means interposed between eaCh end of an intermediate roller and the adjacent end of the respective outer roller, each of said valve means being connected to the second conduit means and having a valve body mounted on said intermediate roller and a valve closing member mounted on the adjacent end of the respective outer roller whereby lifting of any one of said probe rollers due to the presence of foreign material or of a partly folded-over sheet opens one of said valves causing escape of pressure fluid from the second conduit means, said escape increasing the pressure differential across the diaphragm thereby changing the switching position of the switch means, and said second control means further including a relief valve means connected to the first conduit means and having a movably mounted valve body and a valve closing member supported on the other end of one of the outer probe rollers whereby shocks experienced by the probe means causes the closing member of the relief valve to move into a position opening the relief valve means, said opening of the relief valve means permitting escape of pressure fluid from the high-pressure side of the diaphragm, said escape of pressure fluid causing a decrease of the pressure differential thereby maintaining the switch means inactive.
 10. The device according to claim 9 wherein said first control means further comprise a closed housing, said diaphragm dividing said housing into two compartments, one of the conduits being connected to one compartment and the other conduit to the other compartment, said switch actuating member being supported by the diaphragm for movement in unison with the deflections thereof.
 11. The device according to claim 9 wherein the valve body of said relief valve means is swingably supported on said shaft. 